Saint Thomas argued that God was hidden to the senses and unknowable through ordinary contemplation. The hidden nature of God explains the need for revelation and, ultimately, for Christ, the Incarnation of God as a man available to the senses.
Deists, of course, took the idea futher arguing that God had entirely withdrawn from the world after creation, some even denying revelation and the miracles of the Bible.
Some might argue, to the contrary, that God is easily perceived (e.g. through the miracles of life or the nature of the world) but most would agree that the secular world is far more immediate and easily perceived. Science is the systematic investigation of the world and science will never find God.
So why is God hidden?
One theory is that God is playing hard to get. God withdraws so that we have to make an effort to seek and pursue.
But another possibility is that God does not want to dominate our lives but seeks to give us some room to discover things on our own, to make mistakes and recognize our own limitations. To order our societies and build civilizations by our own hands.
What do you think?